Messages in this thread | | | Date | Mon, 14 Sep 2009 00:03:20 +0200 (CEST) | From | Jesper Juhl <> | Subject | Re: [GIT PULL] sched/core for v2.6.32 |
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On Sun, 13 Sep 2009, Mike Galbraith wrote:
> On Sun, 2009-09-13 at 00:07 +0200, Jesper Juhl wrote: > > On Sat, 12 Sep 2009, Ingo Molnar wrote: > > > > > > It was a statistical property based on performance considerations - > > > and now we flipped it around based on latency and for kbuild > > > performance/throughput reasons: Serge Belyshev reported a 7% > > > increase on a quad due to this change and i measured a 1.5% > > > peak-kbuild performance increase. > > > > > Impressive. I wouldn't have expected that much gain by running the parent > > first. Actually I personally would have expected child-first to perform > > better since (in my experience) it's usually the child that's just forked > > that matters the most. > > How can waiting for child1 to run a bit before forking off child2 _not_ > hurt? The parent is the worker bee creator, the queen bee if you will. > Seems to me that making the queen wait until one egg hatches and ages a > bit before laying another egg is a very bad plan if the goal is to have > a hive full of short lived worker bees. > When I wrote the above, I was thinking of one specific case; a server that receives a request, forks off a child to handle the request and the performance we measure is of how long it takes to handle that single request - and in that specific scenario we want the child to run as soon as possible.
-- Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/ Plain text mails only, please http://www.expita.com/nomime.html Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
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